Method for preparing esters of hydroxyaromatic thioacids



United States Patent Ofiice 3,377,372 Patented Apr. 9, 1968 ABSTRACT OF THE DISCLQSURE The method for preparing esters of aromatic, thioacids by the rearrangement of the corresponding aryl ester of S-alkyl thio-carbonic acid.

Cross reference to related applications This application is a continuation-in-part of our earlier filed application Ser. No. 342,281, entitled, Esters of Hydroxy-Aromatic Thioacids, filed Feb. 3, 1964, our U.S. Patent No. 3,338,947; which is in turn a continuation-inpart of our Ser. No. 140,998, filed Sept. 27, 1961, entitled, Esters of Hydroxy-Aromatic Thioacids, now abandoned.

Summary of invention In accordance with the present invention, an aryl ester of S-alkyl thio-carbonic acid is heated in the presence of a Friedel-Crafts catalyst until evolution of HCl ceases. The result of such operation is the rearrangement of the ester to form the hydroxyaryl thioate. The reaction conveniently can be illustrated by the following equation:

AlCl oumea xnornutotmsmu Ol90 C. (I)

wherein R represents a primary aliphatic radical having from 1 to 18 carbon atoms or aryl, n represents an integer from 1 to 2, Ar represents an aromatic nucleus. The preparation of the ester which can be rearranged follows the general equation:

The symbols Ar, n and R have the aforesaid significance. The compounds (I) are useful for the control and eradication of undesirable vegetation. Further, some of these compounds have utility as fungicides. The hydroxy compound employed to prepare the ester in accordance with Equation 11 can be substantially any aromatic hydroxy compound which has an ortho or para position free from substituents and which contains no substituent reactive under the condition of reaction other than aromatic hydroxyl, nor nitro, cyano, or other strongly deactivating group. Thus, the aromatic nucleus is derived from a hydroxyaromatic compound of the benzene series or naphthalene series, a diphenol or alkylene bisphenols (hereinafter referred to as phenols), havingat least one position ortho or para to the hydroxyl free of substitution. It is to be understood that the aromatic nucleus can be substituted with halogen, alkoxy, alkyl and other substituents not reactive under the conditions of reaction. Some of such compounds useful in accordance with the present in vention providing the aromatic nucleus are the phenols, i.e., the cresols, the methoxyphenols, the monoand polyalkylphenols, the phenylphenols, the alkylidene bisphenols, the diphenols, and the resorcinols and the like as well as their alkyl-, alkoxyand halo-substituted derivatives. Exemplary of the above classes are phenol,

m-, or p-cresol, 3,5- 3,4-, 2,4-, 2,3- or 4,5-dialkylphenols, diphenol, o-, por m-alkoxyphenol, p-chlorophenol, 2-chloro-4-methylphenol, naphthol, 2,2-isopropylidenebisphenol, methylenebisphenol, resorcinol and the like.

The thiochloroformates which can be employed to p epare the esters in accordance with the Equation H are those having the formula wherein R represents a saturated primary aliphatic hydrocarbon radical having from 1 to 18 carbon atoms, aryl, or alkylaryl or their halogenated derivatives. Some of such compounds which can be employed are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl tbiochloroformate and all of their primary isomers and halogenated derivatives, as well as phenyl, alkylphenyl, halophenyl, alkylhalophenyl thiochloroformates and the like.

The reaction conditions for carrying out the thiol ester formation are:

Temperature: 0 to about C. and preferably about room temperature.

Time: The length of time of reaction is not critical, some of the desired ester being produced in several minutes. However, at room temperature, mostcsterifications require from several minutes to several hours or even several days when operating at 0 C.

Solvents: When the organic bases are employed as hydrogen chloride acceptors no solvent is usually necessary. However, in some instances, an inert solvent facilitates the reaction. When the inorganic bases are employed as hydrogen chloride acceptors, it is advantageous to employ them in aqueous solution. Thus water becomes the reaction solvent.

Hydrogen chloride acceptors: Substantially any organic or inorganic base can be employed as a hydrogen chloride acceptor. Preferably, however, the tertiary amines and alkali metal hydroxides are employed because of ready, inexpensive availability, ease of handling and, in the case of the organic tertiary amines, ease of recovery and regeneration. Thus one can employ the tertiary amines such as pyridine, trimethylamine, triethylamine, the alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and the like.

The reaction conditions for carrying out the rearrangement reaction of the present invention are:

Temperature: 0 to about 180 C. Above about 180 C. side reactions occur which reduce the yield of desired product. Heating should be discontinued upon cessation of evolution of HCl.

Time: The length of time of reaction is not critical, some of the desired product being produced even with relatively short periods of reaction. The reaction usually is carried out until the evolution of tion continues for about 15-30 minutes at the higher end of the temperatures, two to four hours at the intermediate temperatures and for from one to several days when operating at the lower end of the temperature range.

Solvent: Substantially any inert organic solvent can be employed. Thus one can employ carbon disulfide, the halogenated saturated aliphatic hydrocarbons such as tetrachloroethane, the substituted benzenes such as nitrobenzene, the halogenated benzenes, such as dichlorobenzene, and the like.

Catalyst: Any Friedel-Crafts Representative of such are AlCl SnCl TiCl BF ZnCl ZnBr AlBr SnBr TiBr, and the like. The amount of catalyst is not critical. However, best results are obtained when the catalyst is employed in about equimolar proportions.

catalyst can be employed.

HCl ceases. The reac- 3 4 DESCRIPTION OF PREFERRED EMBODIMENTS such as pyridine, the alkali metal hydroxides such as so- One manner of preparation of the starting thiocarbonic 1 hydroxlde and the the latter as aquequs P acid ester is hereinafter set forth: tions, at about room temperature unless otherwise 1nd!- cated. Upon completion of the reaction the desired product GENERAL PREPARATION (ESTER) is recovered by distillation under reduced pressure. The

The phenol (hydroxyarornatic nucleus) is reacted with reactants, conditions of reaction and products are set forth the thiochloroformate in the presence of an HCl acceptor below:

Example Hydroxyl Reactant HCl Acceptor R Product (M.P.) orB.P., Percent v No. or Base 0.1mm. Yield 1 2 1 OH C5H5N Me 3 8085/0.8 33

1 o o-o-s c H;

2 OH C5HaN Me fl) 140715 Q (})C-S C Ha 1 Cl :1: O1

3 (RH C H N Me (])I 135ll5 O o-cs cm i CH3 4 (|)H C5H N Me (I)! l15117l12 78 O -SCHa -CH3 i O-GHJ 5 1 11 C5H5N IIC H (ijl) O (|)CSC12Hz5 C Ila I CH ' l? 6 0-C 0H 0511513 12 25 [0 scmHi31= (4547) 7 EH1 C H5N Me (I) 161/0.25 77 (!)-CS CH:

3 )H NaOH p-ClGgH; fl) (94-96) 72. 6

"AKOH)g+noid( 'sR- Ai{o0 oisn Example 7 HydroxylRe-actant v. vH01 Acceptor R v Product (M.P.)orB.P., Percent No. or Base CJmm. Yield 1 2 9 OH C5H N. 0 C. Me fl) l078/0.8

OCSCH:

CH CH3 CHw- CH3 l0 OH C5H5N Me (H) 87.4

0- SCHa OH (H) 11 OH V C H5N Me 8693/O.4 80

O-G-SCH:

12 on C5H N Me 3 uz-ns oa 0- SCH3 1 Based on thiochloroformate feed. 2 Yields reported are for purified materials. 3 Aqueous.

GENERAL PROCEDURE (REARR-ANGEMENT) C. until the evolution of HCl ceases. Any solid formed The thio-carbonic ester of the phenol obtained by reacduring the reaction is removed by filtration and the detion above outlined is mixed with an equirnolar proporsired product recovered from the filtrate by extraction tion of a Friedel-Crafts catalyst (AlCl Was used in the with an ether-hexane extractant. The extractant is reexamples) and preferably with an inert solvent (ortho- "1'1'10Ved by distillation to yield the desired hydroxyar'ylcardichlorobenzene has been employed ,iriethe examples). boxylic ester. The products obtained and the reaction The resulting slurry is heated at from about 20 to 180 conditions employed are set forth in the following table:

Ex. Reactant -Temp., Method of Purification Product B.P., C. Yield 1 2 No. C. N H (M.P.)

13 140450 Steam Distilled (|)H -100 (2 mm.) 26

0-0 S C Ha [I l O-SCH1 Recrystallized Isooctane (I)H (120422) 16 I r he a .2. .7 .7 CHsSL=0 14 O Recrystallized Methanol (1)11 (7749) 50 O-G-SOH: a I ll -CSCH Ex. Reactnnt Temp., Method of Purlficatlvn Product Bl. C. Yleld 1 1 N 1 I I (M.P.)

(i? 7 1204.30 Distilled (H1 0 125-130 (3 mm.).

0-0-soH= II I C--SCH;

I CH CH3 16 (H) 160 Steam Distilled--. (|)H O 25 OCSCH; H

I CH G--SCH3 I]! 01330 CH SC=O 17 (I? -140 Recrystallized [rom acetic acid.. CH;S-(|J=O (85-38) 20 CH3S-C-0 18 0 120 Distilled. -3 (1?H 0 18 O-G-SCH:

-CSGHa 19 R 3 95 Rectystallized Methanol (|)H 0 (61435) 60 0--C45OH3 II I G-SCHa CH CH CH3- CH3 2O O do OH ll 1 0 O-C-SGHa II I C-SCH:

OH 0--IJ-SCHa I OH3S-C=O 21 (I? Steam Dlstlllatlon OH 0 (69-71) 50 O-G-SCHa I C-SGH;

22 (H) 95 Distilled (|)H 0 140-145 20 I C-BOH:

HaC-0 HaC-O- u 3 ..-..do-......-..--.-.-..-.....3-.-. 0H 224/3.5..---

OCSG1:H:5 II

I CSCHHII 1 Based on thiochlorotormate lead. fiilellds reported are (or purified materials.

3,377,372 9 10 EXAMPLE 24 3. The method of claim 1 wherein said starting com- To illustrate the usefulness of the compounds having pound Is the generic Formula I as a herbicide, tests were carried out to determine the effectiveness of the named compounds as inhibitors to control the marigold. 5

The test compound was dispersed in water to prepare an aqueous composition containing 100 parts by weight of the compound per million parts by weight of ultimate mixture. This composition was employed for the treatment of seed germination beds which had been prepared and planted with the seeds of marigold. In the treating e ()1 operations, the composition was applied to the seed beds as a drench and at a dosage of about 0.23 acre inch of aqueous composition per acre. Other seed beds similarly prepared and planted were left untreated to serve as checks.

After about eleven days, the seed beds were examined 0 to ascertain what control of the growth and germination B v of seeds had been obtained. The results are set forth in 3 the following table.

4. The method of claim 1 wherein said starting compound is Percent Kill of Ex. No. Test Compound Marigold Seeds and Seedlings 24 Salicylic acid/thiol, methyl ester. 100 25 25 2,3-eresotic acid/thiol, methyl ester 100 26 2,5-eresotic aeid/thiol, methyl ester 100 In other tests, some of the compounds were found effective in the control of the Marine Borer Limnoria, method of clam 1 Where! Sam starting others as aquatic herbicides and the like. 30 Pound 15 We claim:

1. A method which comprises contacting a compound having the following formula l [-Q0-d-s-C 12 7512 6. The method of claim 1 wherein said starting comwherein n represents an integer of from 1 to 2, R reprepound is sents a radical selected from the group consisting of satu- 40 rated primary aliphatic hydrocarbon radicals having from 1 to 18 carbon atoms, phenyl, alkylphenyl, halophenyl and alkylhalophenyl and wherein H SCHa represents a member selected from the group consisting of phenyl, hydroxyphenyl, methylphenyl, dialkylphenyl, alkoxyphenyl, halophenyl, biphenylylene, naphthyl and biphenyl with a Friedel-Crafts metal halide catalyst at from 0 to about 180 C. in the presence of an inert organic solvent until evolution of HCl has substantially ceased, thereby to rearrange said compound to a product 7. The method of claim 1 wherein said starting compound is 0 comprising at least one of the compounds represented by v H the configuration 3 0 Ar (i l-SR) (0H) ('11 J31 whereln each OH is ortho or para to a CSR group 5 8. The method of claim 1 wherein said starting comound is 2. The method of claim 1 wherein said starting comp pound is 0 0 g H sCH OCSCH3 CH -CH3 11 v 12 v 9. The method of claim 1 whrein said starting com- 11. The method of claim 1 wherein said starting compound is pound is Q ll 0 O-G-SCHa 5 O-lE-SCHa H 0C-SCH3 01-130 10. The method of claim 1 wherein said starting com- 10 pound is References Cited UNITED STATES PATENTS 0 i o--sGH: Miyaki et -al.: J. Pharm. Soc. (Japan), vol. 76, pp.

CHARLES B. PARKER, Primary Examiner. CH3 D. R. PHILLIPS, Assistant Examiner. 

